The lock button on the Xiaomi phone does not work: all the reasons and methods of repair

You pressed the lock button on Xiaomi, but the screen didn't go out -- or does the phone stop turning on after you press? -- This problem is common on both the new Redmi Note 12 Pro+ and the old Mi A2, and it can be both mechanical damage and software failures. In 60 percent of cases, the malfunction is fixed without a service center, just reset the settings or clean the connector. But sometimes you need to change the button or even the motherboard.

In this article, we’ll look at all the possible reasons why the lock button on Xiaomi doesn’t work, from the usual pollution to serious hardware breakdowns, how to diagnose the problem yourself, what manipulations can be done at home, and when to contact specialists right away, and we’ve collected step-by-step instructions for each case, including alternative ways to lock the screen if the main button fails.

We will focus on models with a touch power button (for example, Xiaomi 13 Ultra or Mix Fold 3), where a malfunction is often associated with a failure of the control chip. For these, we will give separate recommendations. If your phone gets into the water, fell or overheated, there is a section in the article with emergency measures to help avoid aggravating the breakdown.

1. Software failures: when firmware or settings are to blame

In 30 percent of cases, the lock button stops working because of software problems, not physical damage. The good news is that these malfunctions are often fixed without disassembling the phone.

• 🔄 System freeze after update MIUI Or install custom firmware. The button may not respond due to driver conflict.
• 📱 Failure of the service android.policy – it is responsible for processing the pressing of the power button.
• ⚙️ Incorrect gesture settings (for example, if Touch Only buttons are enabled on physical button devices).
• 🛑 Blocking the button with third-party apps (antiviruses, power saving programs, or parental controls).

The first thing you need to do is force the phone to restart, and to do this, press the Power Button + Volume Up combination for 10-15 seconds (some Xiaomi models have Power + Volume Down). If the phone vibrates but does not reboot, try plugging it into charging and repeating the manipulation.

If the reboot didn’t help, check if any app blocks the button:

1. Open Settings → Applications → Application Management.
2. Sort the list by installation date and remove the recently added programs.
3. Pay attention to applications with the rights of the Administrator of the device (Settings → Passwords and security).

Mechanical damage: what breaks inside the button

Physical breakdowns are the most unpleasant category of malfunctions, as they often require repairs.

• 🔧 A micro-switch is a contact group that closes when pressed. Over time, the contacts become oxidized or erased.
• 🧲 Spring mechanism – if the button “fails” or is pressed too easily, the spring may have flung out or deformed.
• 💧 Sealing rubber - on models with protection IP53 (For example, Redmi Note 11 Pro) it prevents dust, but when worn, it lets moisture through.
• 🔌 The button plume - departs from the motherboard when falling or after careless disassembly.

A critical sign of mechanical failure: the button works "once" or only works when pressed strongly/determined (for example, if you press the top edge). In this case, the problem is definitely not the firmware. Also note the foreign sounds when pressed - creaking, crunch or clicks indicate damage to the internal parts.

To confirm the hardware malfunction, run the button test through the engineering menu:

#4636## → Testing → Power button

If the test shows that the clicks are not fixed, and alternative methods of blocking (for example, through Settings → Lock screen) work, it is the button that is to blame.

3. Moisture infestation: how to save the phone if it gets wet

Even if your Xiaomi has IP53 or IP68 protection, moisture can knock out the lock button. Water penetrates through the microgaps, oxidizing the micro-switch contacts or the plume. Signs of water failure:

• 🌊 The button has become "viscous" or pressed with effort.
• ⚡ The phone spontaneously reboots when pressing on the power.
• 🔋 The battery quickly goes down (moisture creates parasitic currents).
• 🔍 Under the button, traces of corrosion (green or white plaque) are visible).

Emergency measures if the phone is wet:

1. Turn off the device immediately (if it responds to pressing).
2. Extract. SIM-Memory card and card – they can close contacts.
3. Wet the phone with a napkin, but do not shake or blow a hair dryer (this disperses moisture inside).
4. Place your phone in a silica gel bag (out of a shoe box) for 24 to 48 hours.

⚠️ Warning: Do not use rice to dry, as particles of rice can get into the connectors. If the button does not work after drying, do not turn on the phone until repairs: this can lead to a short circuit on the board.

If the moisture has been in the past (a week or more ago) and the button has just failed, it is likely that the contacts will corrosion, in which case only professional ultrasound cleaning or changing the button will help.

4. Alternative ways to lock the screen if the button is broken

While you're looking for a solution or waiting for parts to be repaired, you can lock the screen in other ways. Here are all the methods that work for Xiaomi:

If none of these methods are suitable, you can temporarily disable the screen lock (not recommended for safety):

1. Go to Settings → Lock screen → Lock type.
2. Select No (no password).
3. Install the Gravity Screen app from Play Market to automatically lock when stacking your phone with the screen down.

5. How to disassemble Xiaomi and clean/replace the button yourself

If you decide to repair yourself, you will need:

• 🔧 Setting screwdrivers PH00 and T3 (Xiaomi often uses “stars” for its products").
• 🧲 Screen suction cup.
• 🔥 Fryer (for softening glue).
• 🧴 Alcohol (isopropyl, 90%+).
• 📦 New power button (cost – 200-800) ₽ model-wise).

The following is the example of Redmi Note 9 Pro:

1. Turn off the phone and remove the tray for SIM-map.
2. Heat the hair dryer around the perimeter (temperature ~60 ° C) for 2-3 minutes.
3. Put a plastic blade on the lid, starting at the corners. Be careful, the fingerprint scanner plume is often glued to the lid!
4. Unscrew 12 screws that fix the metal plate.
5. Disconnect the battery plume (black connector labeled BATT).
6. Find the power button plume (usually to the right of the battery,marked) PWR_KEY). Unplug it.
7. Remove the old button and install the new one with the B-7000 glue.

⚠️ Attention: On Xiaomi models 12/13 The power button is integrated into the middle frame, and it requires a complete disassembly of the phone to replace it, and it's best to trust the professionals to do it.

If the button is just dirty, try cleaning it without disassembling:

1. Put the alcohol on the cotton swab.
2. Carefully scroll the stick around the button, pressing slightly.
3. Repeat 3-4 times, then let the phone dry for 10 minutes.

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Before you assemble the phone, check the tightness of the sealing rubber bands. If they break, replace them, otherwise the dust will quickly disable the new button.

6. When a replacement motherboard is required

In rare cases (about 5% of the failures), the lock button does not work due to damage to the motherboard.

• ⚡ Short circuit (for example, after moisture hits the board).
• 🔥 Overheating (if the phone worked under load for a long time without cooling).
• 💥 Impact (falling on a hard surface can damage board tracks).
• 🔌 Incorrect firmware (if the phone was “sweetened” with errors, the power controller could burn down).

Signs of payment problems:

• The phone does not turn on at all (even when connected to charging).
• The lock button does not work, but there is vibration when pressed (it means that the signal reaches the board, but is not processed).
• Artifacts appear on the screen or the phone goes into a bootloop (cyclic reboot).

Diagnostics of circuit board damage require special equipment (multimeter, oscilloscope) and service centers check:

• Integrity of tracks from the power button to the PMIC (Power Management IC) chip.
• The voltage at the button contacts (should be ~1.8V at rest and ~0V at pressing).
• Qualcomm PMI8998 (on Snapdragon) or MT6360 (on MediaTek)

⚠️ Note: If the wizard offers to "re-sweeten" the chip on the board, check whether it gives a guarantee. soldering connections on multilayer Xiaomi boards often fall off after 1-2 months.

The cost of replacing the fee on Xiaomi:

• Redmi 9/Note 9: 3 000–5 000 ₽.
• Xiaomi 11T/12 Pro: 8 000–12 000 ₽.
• Mix Fold 2/3: 15 000–25 000 ₽ (due to the complexity of disassembly).

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If the phone is warranty, don't disassemble it yourself! opening the case will void Xiaomi's warranty obligations.

7. Frequent questions about a broken lock button